Polyurethane coating (PU coating)
Also known as: PU coating, polyurethane finish, PU-coated fabric
Cost-effective, elastic polyurethane layer applied to textiles for waterproofness — less breathable than silicone and prone to hydrolysis.
Description
In a PU coating a textile substrate — usually polyester or nylon ripstop, more rarely cotton — is coated on the back with a thin, closed polyurethane layer. The layer is applied as a solution or dispersion, drawn off with a doctor blade and then dried or heat-set. The hydrostatic head is typically between 1,500 and 10,000 mm depending on build — enough for classic rainwear, tents, backpacks, rain ponchos, oven mitts, shower curtains and protective covers.
Advantages: PU is elastic, adheres very well to synthetic substrates, is easy to glue (seam tape) and is significantly cheaper than silicone. Drawbacks: lower breathability and hydrolytic degradation over time — the PU becomes sticky or crumbly after years, especially in humid storage. UV light and heat accelerate ageing. Silicone coatings and TPU membranes last longer but cost more.
- Application: doctor-blade / direct coating
- Typical hydrostatic head 1,500–10,000 mm
- Easy to sew and to seam-tape
- Prone to hydrolysis — limited lifetime
Properties
| Principle | Direct-coating with doctor blade on substrate |
|---|---|
| Hydrostatic head | approx. 1,500–10,000 mm |
| Weaknesses | Prone to hydrolysis, lower breathability |
Related product categories
Sources & references
2- Wikipedia: Polyurethane Wikipedia — Freie Enzyklopädie https://en.wikipedia.org/wiki/Polyurethane
- Wikipedia: Coated fabrics Wikipedia — Freie Enzyklopädie https://en.wikipedia.org/wiki/Coated_fabric
